In the display skill field, Liquid Crystal Display (LCD), Organic Light Emitting Diode (OLED) and other panel display skills have been gradually replaced the CRT displays. The OLED possesses many outstanding properties of self-illumination, low driving voltage, high luminescence efficiency, fast response, high clarity and contrast, near 180° view angle, wide range of working temperature, applicability of flexible display and large scale full color display. The OLED is considered as most potential flat panel display technology.
At present, the most significant issue restricting the development of OLED industry and the biggest defect of the OLED is the shot life time of the OLED. The root cause of the shot lifetime for the OLED is the electrode and organic material are extremely sensitive to the moisture and the oxygen. Therefore, an efficient package of preventing the moisture and the oxygen into the interior of the OLED is very important for extending the lifetime of the OLED and guaranteeing the performance of the OLED.
The key of the efficient package for the OLED is to control the package quality during the factory manufacture of the OLED for ensuring the availability of the OLED elements. The package of the OLED can be categorized and mainly comprises several types of: drier package, UV glue package (Dam only), UV glue and underfill package (Dam & Fill package), glass glue package (Frit package) and etc. Among these, the Dam & Fill package possesses advantages of simple art, applicability of large size package, flexible package procedure, stability and reliability and etc. More and more applications have been derived therefrom and the manufacture cost can be effectively reduced.
Package is implemented by the package device. Therefore, the package device is the footstone of guaranteeing the validity of OLED element package. In general, the package line of the OLED element package mainly comprises Buffer, USC, Loader, Multi, VAS, UV Cure, Unloader and etc. The main function of the VAS is to laminate the OLED substrate and the package plate. The quality of the lamination directly affects the package result. The VAS is the one of the most significant and important devices in the package line.
As shown in FIG. 1 and FIG. 2, the present package method of a Dam & Fill package method of the OLED panel is: coating seal glue continuously on a package plate 100 to form an inner glue frame 200 and an outer glue frame 300; underfill 400 is dispensed drop by drop and intermittently; then, package plate 100 and the OLED substrate are laminated in a VAS machine. Because the viscosity of the underfill 400 is lower, the underfill 400 is spread to fill in the area surround by the inner glue frame 200 under pressure during the lamination process; finally, an UV light is utilized to irradiate the seal glue and the underfill and solidify both. Accordingly, packaging the OLED substrate by the package plate 100 is realized.
However, in actual manufacture processes, gaps among the droplets of the underfill 400 may become bubbles after the lamination of the package plate 100 and the OLED substrate. However, the coefficient of viscosity of the underfill 400 is large and for the bubbles in the underfill 400 it is hard to over come the drag force to be drawn out. The situation of remaining bubbles because underfill 400 cannot fill in the area surrounded by the inner glue frame 200 may often occur and affect the performance and the lifetime of the OLED elements. The issue of existing bubbles in underfill which is under filled can be solved by improvement of the VAS device.